A carbon material etc. that stores and releases lithium is currently used as the electrode for lithium batteries, but there is a risk of decomposition of the electrolytic solution since the negative potential is lower than the reductive decomposition potential of hydrogen. Accordingly, as described in Patent Documents 1 or 2, the use of lithium titanate having higher negative potential than the reductive decomposition potential of hydrogen is being investigated, but lithium titanate has a problem of low output property. Accordingly, attempts are being made to improve output property by an electrode in which lithium titanate is made into nanoparticles and supported on carbon.    Patent Document 1: JP 2007-160151 A    Patent Document 2: JP 2008-270795 A
The inventions described in these Patent Documents are methods for applying sheer stress and centrifugal force to a reactant in a rotating reactor to allow promotion of chemical reaction (generally referred to as mechanochemical reaction), thereby yielding dispersed lithium titanate supported on carbon. In this case, for example, titanium alkoxide and lithium acetate which are the starting materials of lithium titanate, a carbon such as carbon nanotube or Ketjen Black, and acetic acid etc. are used as reactants.
Although the electrodes that use carbon supporting lithium titanate nanoparticles described in these Patent Documents exert superior output property, there are recent demands to further improve the output property and to improve the electric conductivity in this type of electrode.
The present invention is proposed to solve the problems of the conventional technology as stated above, the object of which is to provide lithium titanate nanoparticles that enable the output property and electric conductivity to be improved when the electrode is configured by doping oxygen vacancy (also called oxygen defect) portions with nitrogen, a composite of lithium titanate nanoparticles and carbon, and a method of production thereof. In addition, other objects of the present invention is to provide an electrode material that employs said composite, an electrode, an electrochemical element, and an electrochemical capacitor that employ this electrode material.